Population biology of Callichirus major (Say, 1818) (Crustacea: Callianassidae) at Piedade Beach, Brazil

Abstract

The aim of this paper was to study the population ecology of Callichirus major (Say, 1818) at Piedade Beach, State of Pernambuco, Brazil, through the analysis of parameters such as sex ratio, reproductive period and recruitment of juveniles into this population. Sampling was taken monthly from December 2010 to November 2011. The burrow and air temperatures, as well as the sea water salinity, were measured in situ. A Student t test was applied to compare the value of abiotic factors between the dry and rainy seasons. The sex ratio was analyzed for each month and for the total studied period, and a Chi-square test was applied to verify if it deviated significantly from the expected proportion. The reproductive period was determined based on the frequency of ovigerous females. The recruitment was obtained based on the frequency of nonmature individuals. The influence of the abiotic factors was evaluated through a Pearson’s coefficient. The air and burrow temperatures varied significantly between the dry and rainy periods, with the highest values in the dry period. A total of 389 individuals of C. major (174 ♂ and 215 ♀) were sampled. The sex ratio was 1:1.24 (♂:♀), with females being more abundant than males. In this study, the most active reproductive period of C. major and frequency of ovigerous females was observed in the dry period (equatorial summer). Recruitment of juveniles into the population occurred throughout the year, between the summer and the autumn. According to the correlation matrix, the main abiotic factor influencing the abundance of C. major, especially of ovigerous females, was the burrow temperature. This study creates a baseline for further research with C. major in Northeastern Brazil.